This project involves a number of related studies of chronic disease or cancer epidemiology. It includes a preliminary investigation into the etiology of Reye's Syndrome; an investigation into the relationship of maternal smoking and childhood cancer; an investigation into the relationship of selenium and other trace elements to skin cancer; an investigation of occupationl exposure to hair dyes and the occurrence of death from breast cancer; and an investigation of the relationship of estrogen receptors to other known risk factors for breast cancer.